Digital cameras are widely used, which convert an optical image of a subject as captured through an imaging device like a CCD image sensor, to digital image data and record the image data in a recording medium like a memory card. A lens-interchangeable digital camera has recently been suggested, for example by Japanese Laid-open Patent Application No. 2000-187268, wherein a lens unit containing an optical system and an imaging device is detachably attachable to a camera body. Since the imaging device is mounted in combination with the optical system in the lens unit, this kind of lens-interchangeable digital camera has advantages in that the user can select a suitable lens unit depending upon the scene to shot, that it is unnecessary to adjust position of the optical system to the imaging device at the interchange of the lens unit, and that the imaging device is always protected from dusts.
However, since the prior lens-interchangeable digital camera is simply divided into the lens unit served as an imaging section and the camera body served as an image processing, recording and displaying section, the usage of the camera body without the lens unit is confined.
Also because a grip of the prior lens-interchangeable digital camera is integrally formed with the camera body, the grip is not always optimum for any kinds of interchangeable lens units whose size and shape are variable. Generally, a large grip is desirable for a large lens unit, for the sake of steady gripping or holding of the camera.